package forth

import "fmt"



type Stack struct {
    stack []int
    ptr int
}

func (s *Stack) Push(k int) {
    s.stack = append(s.stack, k)
}

func (s *Stack) Pop() (int, error) {
    if len(s.stack) == 0 {
        return 0, fmt.Errorf("cannot pop empty stack")
    }
    
    el := s.stack[len(s.stack)-1]
    s.stack = s.stack[:len(s.stack)-1]
    return el, nil
}